Overview of Charm Production - J/'s and Open Charm

Heavy quark production provides a sensitive window for the study of the gluon structure of nucleons and its modification in nuclei. It also provides a very important means of studying the hot-dense conditions created in high-energy collisions of heavy nuclei and a critical probe to look for de-confinement in this hot-dense matter. I will review, from an experimental point of view, the physics issues as seen in current experimental results for charm production and point out the remaining puzzles.